Diazonium Research Articles

Boron-doped diamond nanosheet volume-enriched screen-printed carbon electrodes: a platform for electroanalytical and impedimetric biosensor applications

This paper focuses on the development of a novel electrode based on boron-doped diamond nanosheet full-volume-enriched screen-printed carbon electrodes (BDDPE) for use as an impedimetric biosensor. Impedimetric biosensors offer high sensitivity and selectivity for virus detection, but their use as point-of-care devices is limited by the complexity of nanomaterials’ architecture and the receptor immobilisation procedures. The study presents a two-step modification process involving the electroreduction of diazonium salt at the BDDPE and the immobilisation of antibodies using zero-length cross-linkers for a selective impedimetric biosensor of Haemophilus influenzae (Hi). The incorporation of diamond nanosheets into BDDPE leads to enhanced charge transfer and electrochemical behaviour, demonstrating greatly improved electrochemically active surface area compared with unmodified screen-printed electrodes (by 44% and 10% on average for [Ru(NH3)6]Cl2 and K3[Fe(CN)6], respectively). The presented sensing system shows high specificity towards protein D in Hi bacteria, as confirmed by negative controls against potential interference from other pathogens, with an estimated tolerance limit for interference under 12%. The Hi limit of detection by electrochemical impedance spectroscopy was 1 CFU/mL (measured at − 0.13 V vs BDDPE pseudo-reference), which was achieved in under 10 min, including 5 min sample incubation in the presence of the analyte.Graphical abstract

Recent Advances in the Synthesis of Aromatic Azo Compounds.

Aromatic azo compounds have -N=N- double bonds as well as a larger π electron conjugation system, which endows aromatic azo compounds with wide applications in the fields of functional materials. The properties of aromatic azo compounds are closely related to the substituents on their aromatic rings. However, traditional synthesis methods, such as the coupling of diazo salts, have a significant limitation with respect to the structural design of aromatic azo compounds. Therefore, many scientists have devoted their efforts to developing new synthetic methods. Moreover, recent advances in the synthesis of aromatic azo compounds have led to improvements in the design and preparation of light-response materials at the molecular level. This review summarizes the important synthetic progress of aromatic azo compounds in recent years, with an emphasis on the pioneering contribution of functional nanomaterials to the field.

Synthesis of Some Azo Dyes Based on 2,3,3-Trimethyl-3H-indolenine

New azo compounds on the base of 2,3,3-trimethyl-3H-indolenine were synthesized and characterized by FT-IR, NMR, and Mas-spectral analysis. The synthesis was conducted in three different pathways: 1) by reducing the nitro compound with Zn/NaOH in alcohol; 2) by heating of 2,3,3-trimethyl-3H-indolenine-5-amine in the presence of MnO2 in toluene, and 3) by diazotization of 2,3,3-trimethyl-3H-indolenine-5-amine and treating the resulting diazonium salt with the appropriate coupler.

Synthesis and characterization of a new azo quinoline ligand and its metal complexes with spectrophotometric determination and biological efficacy study of its Hg(II) complex

ABSTRACT. An azo quinoline ligand, (E)-2-((4-iodophenyl)diazenyl)-8-hydroxyquinoline (IPDHQ), was synthesized by the coupling reaction of 4-iodoaniline diazonium salt with 8-hydroxyquinoline. The synthesized ligand and its Cd(II), Pd(II), Cu(II) and Hg(II) complexes were spectrally characterized by UV‒Vis spectrophotometry, FT-IR, mass spectral analysis, 1H-NMR, magnetic sensitivity and molar conductivity. The general formula of the Cd(II), Cu(II) and Hg(II) complexes is [M(L)2].Cl2.H2O with octahedral geometry, while the general formula of the Pd(II) complex is [M(L).Cl2].H2O with square planer geometry. A simple and rapid spectrophotometric procedure was suggested for the determination of Hg(II) using the synthesized ligand as a spectrophotometric reagent. By measuring the absorbance for the resulting orange complex at 430 nm, the linearity range was 0.5-15 µg mL-1, and the interfering effect was also studied. The synthesized azo ligand and its Hg(Ⅱ) complex were tested for their biological activity against four bacterial strains.
 KEY WORDS: Azo quinoline ligand, 8-Hydroxy quinoline, 4-Iodoaniline, Azo metal complexes, Spectrophotometric determination, Biological efficacy study
 Bull. Chem. Soc. Ethiop. 2023, 37(6), 1459-1470. DOI: https://dx.doi.org/10.4314/bcse.v37i6.13

New substituted pentazadienes as initiators of free-radical polymerization: synthesis, photochemical properties and perspectives for holographic media

The series of 4,4′-substituted 3-hydroxyethyl-pentaza-1,4-dienes were synthesized in the reaction of aromatic diazonium salts with an ethanol amine. Photolysis of pentaza-1,4-dienes was investigated by means of UV/Vis spectroscopy. Electron donating methyl and methoxy substituents were found to increase photosensitivity whereas electron withdrawing chloro-substituents cause higher photolytic stability. 3-hydroxyethyl-pentaza-1,4-dienes as a radical polymerization initiator has been successfully investigated in 10% methyl methacrylate solution in DMF. Gel permeation chromatography (GPC) and differential scanning calorimetry (DSC) were used for obtained polymers characteristics evaluation. The highest values of PMMA Mn and Đ can be obtained in the case of chloro-substituted derivative. The holograms of a plane wavefront were recorded in media based on obtained PMMA doped by azo-dye by a 532 nm laser in a ∼1-μm-thick sample. The diffraction efficiency values for parallel polarized acting light increased in Cl→Me→OMe series.

Catalytic Photoredox C-H Arylation of 4-Oxo-4H-pyrido[1,2-a]pyrimidine-3-diazonium Tetrafluoroborates and Related Heteroaryl Diazonium Salts.

Irradiation of mixtures of title diazonium salts and heteroarenes with green light (510 nm) in the presence of eosin Y disodium salt (EY-Na2) as a photocatalyst furnished the corresponding arylation products in 8-63% yields. The proposed photocatalytic cycle is analogous to that proposed previously for closely related photoredox C-H arylations with aryl diazonium salts as aryl radical sources. This method has a broad substrate scope and represents a metal-free alternative for the synthesis of 3-heteroaryl-substituted 4H-quinolizin-4-ones and azino- and azolo-fused pyrimidones with a bridgehead nitrogen atom.

Cross‐Coupling Reactions between Arenediazonium o‐Benzenedisulfonimides and Organolithium Reagents in a Deep Eutectic Solvent

AbstractA deep eutectic solvent (DES) based on glycerol and KF is successfully exploited as a solvent medium in cross‐coupling reactions between arenediazonium o‐benzenedisulfonimides and organolithium reagents (Muharashi‐Feringa coupling). The reactions were carried out in open air and in mild conditions. The target products were obtained in fairly good yield (15 examples; average yield: 60 %). This is, on the best of our knowledge, the first example of Muharashi‐Feringa coupling carried out with diazonium salts. A tentative hypothesis of the reaction mechanism was also proposed.

Grafting a Polymer Coating Layer onto Li1.2 Ni0.13 Co0.13 Mn0.54 O2 Cathode by Benzene Diazonium Salts to Facilitate the Cycling Performance and High-Voltage Stability.

Li-rich Mn-based cathodes have been regarded as promising cathodes for lithium-ion batteries because of their low cost of raw materials (compared with Ni-rich layer structure and LiCoO2 cathodes) and high energy density. However, for practical application, it needs to solve the great drawbacks of Li-rich Mn-based cathodes like capacity degradation and operating voltage decline. Herein, an effective method of surface modification by benzene diazonium salts to build a stable interface between the cathode materials and the electrolyte is proposed. The cathodes after modification exhibit excellent cycling performance (the retention of specific capacity is 84.2% after 350 cycles at the current density of 1 C), which is mainly attributed to the better stability of the structure and interface. This work provides a novel way to design the coating layer with benzene diazonium salts for enhancing the structural stability under high voltage condition during cycling.

Electrochemical C–H Arylation of Quinazolinone with Aryl Tetrafluoroborate Diazonium Salts in Aqueous Solution of Ionic Liquids

Electrochemical C–H Arylation of Quinazolinone with Aryl Tetrafluoroborate Diazonium Salts in Aqueous Solution of Ionic Liquids

Rapid Colorimetric Determination of Biologically Active Organic Analytes

Four types of reactions (azo coupling, protolytic and oxidative condensation, ion association), accompanied by the formation of hydrophobic colored analytical forms of corresponding organic analytes, are proposed on an example of biologically active substances (aromatic amines, α-amino acids, antibiotics of aminoglycoside and β-lactam series, anionic surfactants). It is shown that, in these systems, the hydrophobicity of both the initial reactants, e.g., tetrafluoroborates of diazonium salts, and analytical forms (azo compounds, Schiff bases, Ruemann’s purpura, ion associates with surfactants) can be increased. Possibilities of various methods for the derivatization of organic analytes with the formation of colored analytical forms with increased hydrophobicity for the best fixation on solid matrices and the development of test systems on their basis, which can be used to control the quality of various samples with rather good performance characteristics, are considered.

Inhibiting Metal Galvanic and Carbon Corrosion in Aluminum Alloy-Carbon Fiber Reinforced Composite Joints by Spontaneous Deposition of Diazonium Adlayers on Exposed Carbon Fibers

The spontaneous formation of a diazonium molecular adlayer on the exposed fibers of a carbon fiber reinforced polymer (CFRP) composite was investigated as a surface treatment. The purpose of the surface treatment is to reduce the extent of galvanic corrosion on a trivalent chromium process (TCP) conversion-coated aluminum alloy when the two materials are mechanically joined as is common in aircraft structures. The adlayer functions to reduce the rate of dissolved oxygen reduction on the more noble carbon thereby reducing the rate of galvanic corrosion on the more active metal alloy. The formation of the adlayer (4-nitrophenyl (NP), 4-nitroazobenzene (NAB), or 2-fluorene diazonium tetrafluoroborate (FL)) was achieved by immersing the CFRP composite specimen in a solution of 5 mM diazonium salt dissolved in acetonitrile for a specified time (1–24 h) under open circuit conditions (so-called spontaneous deposition). Cyclic voltammetry (CFRP composite) and rotating disk voltammetry (glassy carbon) were used to investigate the oxygen reduction reaction kinetics in naturally aerated 0.5 M Na2SO4 (pH 5–6). The oxygen reduction reaction current was suppressed by greater than 90% by the NP and NAB adlayers and 80% by the FL adlayer. The surface treatment (24 h immersion) with NAB significantly reduced the galvanic corrosion damage on TCP conversion-coated aluminum alloy during a 14-day continuous neutral salt spray (NSS) exposure. The mass loss (mg/cm2) and corrosion intensity (g/m2y) were reduced by over 10×. The spontaneously formed NAB adlayers are stable during the salt-spray exposure and provide better inhibition of galvanic corrosion on the aluminum alloy and resistance to carbon corrosion than do NAB adlayers formed by an electrochemically assisted process reported on previously.

Synthesis, characterization and <i>in-silico</i> studies of (e)-4-[(4,5- dimethylthiazol-2-yl)diazenyl]-2-isopropyl-5-methylphenol and its coordination compounds

An azo dye, (E)-4-((4,5-dimethylthiazol-2-yl)diazenyl)-2-isopropyl-5-methylphenol (L1), was prepared by the reaction of 5-methyl- 2-(propan-2-yl)phenol with the diazonium salt of 2-amino-4,5-dimethylthiazole. Characterization was carried out using proton and carbon-13 nuclear magnetic resonance spectroscopy. Coordination compounds of L1 with Mn(III), Fe(III) and Co(III) in a 1:2 metal to ligand mole ratio were subsequently synthesized. Corresponding mixed ligand complexes were also synthesized using 2- hydroxybenzoic acid (L2) as the secondary ligand. The coordination compounds were characterized by electronic and infrared spectrophotoscopy, magnetic susceptibility measurements, and percent metal composition. Subsequently, in silicostudies were performed based on the proposed structures of the synthesized compounds to determine their binding affinity and binding site with calf thymus DNA. The results obtained showed that all complexes achieved octahedral geometry. The results also showed that some of the compounds had better affinity for CT-DNA than the standard.

Visible‐light‐mediated synthesis of 3‐arylsulfonylated thioflavones using an in situ activation strategy

AbstractWe have developed a visible‐light‐mediated synthesis of 3‐arylsulfonylated thioflavones using an in situ‐activation strategy. The reaction proceeds through a one‐pot, three‐component pathway, without the need for sensitive or harsh reaction conditions. Organic photocatalysts were employed to generate aryl radicals more efficiently from aryl diazonium salts generated in situ. This method enables the synthesis of 3‐arylsulfonylated thioflavones from aryl amines and methylthiolated alkynones, utilizing potassium metabisulfite as an inexpensive source of sulfur dioxide. The resulting products were obtained under mild reaction conditions. This approach provides an efficient alternative pathway for synthesizing thioflavone derivatives, which are prevalent among various bioactive compounds.

(Invited) Stochasticity in the Number of Quantum Defects in Fluorescent Carbon Nanotubes

Single wall carbon nanotubes (SWCNTs) display chirality dependent near infrared (NIR) fluorescence. Their optoelectronic properties can be further tuned by incorporating quantum defects/organic color centers (OCC) via reactions with diazonium salts. The absolute number of defects per SWCNT determines the properties but is not exactly known. Measuring it is complicated because typical SWCNT samples contain multiple chiralities, that congest the spectra and prevents to distinguish defects from different chiralities. Aqueous two-phase extraction (APTE) is a powerful technique to isolate specific chiralities. Here, we show that quantum defects do not affect APTE, which indicates that the chemical potential is not substantially affected and pinpoints to low numbers of defects. The purity of (6,5)-SWCNTs allows us to image the NIR fluorescence contributions (E11 below 1050 nm, and E11 * above 1050 nm) on the single SWCNT level and defect incorporation itself on the single molecule level. Interestingly, one observes a stochastic distribution of the numbers of defects, which can be explained by a Poisson distribution. We find a mean number of defects of 0-3 per SWCNT. These results indicate the large variance between ensemble and single particle picture. In summary, we show that single quantum defects can be counted by NIR imaging and that stochasticity plays a crucial role for their optical properties.

Synthesis, characterization and study anticancer activity of new Azo –Chalcone with mix Ligand of some divalent metal chelate complexes

In this paper azo-chalcone compound was synthesized by coupling paramino-acetophenone with parabromobenzaldehyde to prepared chalcone , and preparing a mixture of azo-chalcone from reacted diazonium salt of Chalcone with Paracetamol new five complexes of divalent ions (Cu, Zn, Ni, Co, Cd) were prepared by mixture azo-chalcone with 8-hydroxy quinoline, The results show that the mole ratio (metal - ligand) is (1:1:1) for all chelates . The ligand characterized by 1HNMR, mass spectrum and its complexes were characterized by microanalysis of the elements, UV-Vis, FTIR, molar conduction and magnetic moment azo- chalcone coordinated via (N) atom of azo group and (O) atom of OH group of Paracetamol with metal ions. Based on the obtained results, an octahedral geometry were proposed for all chelate complexes. The effect of the biological examination of Ni (II) complex was tested antitumor Breast cancer cells and compared with healthy cells to show the possibility of using these compounds in a therapeutic manner.

Expanding Our Cyclodextrin-Based Sensors with Automation and New Surfaces

We have had significant success in building cyclodextrin mediated sensors. We initially started with a gold surface, being able to detect analyte up to three times post modification [1]. Afterwards, we improved the stability and reusability by moving to a phenyl-modified carbon electrode via diazonium salt chemistry [2]. With his new surface, we were able to detect cortisol up to 10 different times with high accuracy, repeatability, and sensitivity in buffer, urine, and artificial saliva. We were limited by manually manipulating the electrode; therefore, we were not able to test the electrode for greater than 10 measurements. Within this poster, we intend to present our ideas and progress towards developing an automated detection system that can be preprogrammed to clean, reset, and test the cyclodextrin-mediated surface with target analytes. Further, we will share our various target analytes and our strategy to expand our sensor surface to include multiple cyclodextrin derivatives.Research supported by New Hampshire- INBRE through an Institutional Development Award (IDeA), P20GM103506, from the National Institute of General Medical Sciences of the NIH.[1] Z. Panahi, M. A. Merrill, and J. M. Halpern, “Reusable Cyclodextrin-Based Electrochemical Platform for Detection of trans -Resveratrol,” ACS Appl. Polym. Mater., vol. 2, no. 11, pp. 5086–5093, Nov. 2020.[2] Z. Panahi, T. Ren, and J. M. Halpern, “Nanostructured Cyclodextrin-Mediated Surface for Capacitive Determination of Cortisol in Multiple Biofluids,” ACS Appl. Mater. Interfaces, Aug. 2022.

Azo Coupling of Indoles Revisited: Synthesis of Biindolyl Photoswitches via the Azo-Coupling/C-H Functionalization Domino Approach.

When azo coupling of aryldiazonium salts with indoles was carried out in aprotic nonpolar solvent on air, a pseudo-three-component reaction has been discovered. Azo coupling is followed by a nucleophilic addition of a second indole unit to the indolium intermediate; aromatization and oxidation are achieved under air.

Approach to Access Benzo[j]phenanthridinones from 1,7-Enynes and Aryldiazonium Salts via a Domino Radical Relay Process Enabled by a P/N-Heteroleptic Cu(I)-Photosensitizer.

A mild approach for the synthesis of benzo[j]phenanthridin-6(5H)-one derivatives from 1,7-enynes and aryldiazonium salts has been successfully developed involving a domino radical relay process enabled by a heteroleptic Cu(I)-photosensitizer under visible-light-driven photocatalytic conditions. Mechanistic studies disclosed that the oxidative quenching of the excited state of PS 4 with aryldiazonium salts via an SET process generated aryl radicals, which could play a radical initiator-terminator dual role within the whole radical relay process, namely, at the initial step acting as a radical donor to trigger the radical addition to the olefin moieties of 1,7-enynes while at the final stage serving as a radical acceptor to complete the cyclization.

Cover Picture: Tetrazole Diversification of Amino Acids and Peptides via Silver‐Catalyzed Intermolecular Cycloaddition with Aryldiazonium Salts (Angew. Chem. Int. Ed. 37/2023)

Cover Picture: Tetrazole Diversification of Amino Acids and Peptides via Silver‐Catalyzed Intermolecular Cycloaddition with Aryldiazonium Salts (Angew. Chem. Int. Ed. 37/2023)

Aryldiazonium Salt-Triggered [2 + 2 + 1] Heteroannulation of Indoles by an Arylhydrazone Radical-Relayed 1,5-Hydrogen Atom Transfer.

An unprecedented three-component [2 + 2 + 1] annulation cascade of indoles with aryldiazonium salts and polyhalomethanes or acetone is presented by dual hydrogen atom transfer (HAT) and C-H functionalization. By employing readily accessible aryldiazonium salts as the radical initiators and electrophiles and polyhalomethanes and acetone as the C1 units, this method unprecedentedly constructs a pyrazole ring on an indole ring skeleton through the formation of two C-N bonds and a C-C bond in a single reaction.